1. Field of the Invention
The present invention relates to image-taking control apparatuses which control the operation of an image-taking device, such as pan-tilt head or the like on which a video camera is mounted. More specifically, the present invention refers to image-taking control apparatuses with which the operation of a plurality of drivable parts in an image-taking device is finished at substantially the same time.
2. Description of Related Art
Image-taking devices in which a video camera capable of a zooming operation and a focusing operation is mounted onto a pan-tilt head capable of a panning operation and a tilting operation are often used for image-taking at remote locations.
When image-taking is performed using such an image-taking device, then an image-taking control apparatus is used which is provided with a shot operation function making it easy to change the image-taking conditions from the current field angle and direction to another field angle and direction. With this shot operation function, the zooming position, focusing position, panning position and tilting position corresponding to the field angle and direction desired by the operator are set (stored) in advance, and it is possible to let the image-taking device move automatically to a stored position by simply ordering the movement to the stored position.
Moreover, image-taking control apparatuses have been proposed which have a synchronized shot operation function allowing changes in field angle and direction which are not irritating, by simultaneously starting and simultaneously stopping the shot operation of a plurality of drivable parts within a preset operation time.
More specifically, the operation speed of all drivable parts is controlled such that the operation times of the other drivable parts are adjusted to the operation time of the drivable part which takes the longest to finish, of the shot operations of the plurality of drivable parts, and the operations of these drivable parts are started simultaneously and finished simultaneously (see Japanese Patent Publication No. S58 (1983)-6163).
However, recently motors whose driving speed can be switched only in steps, such as pulse motors, have come to be used as the driving source of these drivable parts. In this case, sometimes only operation speeds can be selected at which there is a discrepancy to the operation speeds necessary to finish the shot operations of a plurality of drivable parts simultaneously.
In those cases, there will be variations in the end timings of the operations of the plurality of drivable parts, and the characteristics of synchronized shot operation are not attained.